This invention relates to a method and product for preventing yarn tail breakage during yarn winding. The invention disclosed in this application has particular utility in the winding of cones with yarn intended for knitting. These cones are wound with "tails" which permit the trailing end of yarn on an exhausted cone to be tied to the leading end of yarn on the succeeding full package. The tail is necessary if the transfer from the exhausted to the full package is to take place without dropping needles, which causes a serious defect in the knitted fabric.
While the invention disclosed in this application has utility on a number of different types of cones, for purposes of illustration the invention will be described with reference to a tubular textile yarn package which is formed of pressed paper and has a generally frusto-conical shape. While cones come in various configurations, one common type of cone is a cone which has an angle of taper of 5 degrees, 57 minutes.
As described above, this type of cone must be wound with a tail in order for it to be considered a first quality package. The tail is usually formed by taking a length of yarn and extending part of it over the open mouth of the large end of the cone. The cone is then applied to a cradle which has a cone holder base plate which fits into the large end of the cone and holds the yarn, and a cone holder nose plate which secures the cone for proper rotation about a fixed axis. The cone is wound by surface drive against a rotating drum which feeds the yarn onto the rotating cone in a predetermined pattern.
Until relatively recently, winders were designed so that the cone holder base plate had an internal taper which corresponded to the taper of the cone. This meant that for a fairly substantial distance on the order of 1/4 of an inch, the surface of the cone holder base plate and the inner surface of the cone were parellel with each other and in flush contact. The yarn trapped across the mouth of the cone was thereby held firmly along the entire length of contact between the cone and the base plate. This resulted in a secure grip while, at the same time, spread any stress applied to the yarn over a relatively long distance.
However, when it became necessary to change the type of cones being wound, it was necessary to change the cone holder base plate and nose plate to accommodate the new size and/or taper of the new cone. This required substantial labor, expense and, in addition, reduced the maximum possible operating time of the winder with a corresponding loss of operating efficiency.
Therefore, some winder manufacturers have designed cradles which have universal cone holder base plates and nose plates. The plates are adapted to receive cones having various angles of taper without the additional labor and lost operating time required to conform the cradle to the precise type of cone being wound. While substantial efficiencies are achieved by this new type of winder, the angle of the portion of the base plate which fits into the large end of the cone is no longer necessarily parallel to and flush with the inner surface of the cone. Therefore, the yarn tail passes between the cone and the base plate at two diametrically opposed edges rather than wide, flush surfaces. As long as there is little or no relative movement between the base plate and cone, this fact is of little consequence. Therefore, when starting an empty cone, there is little difficulty since the cone itself is very lightweight and has very little inertia. Accordingly, the cone begins rotation with the base plate and there is no relative movement which could cause the yarn to be pinched or cut. However, as yarn is wound onto the cone, it increases substantially in weight and inertia.
Many winders have automatic stop motions which utilize, for example, an air brake to very quickly stop the rotation of cone when the package is full or when a break in the yarn occurs. The substantial inertia created by a full or near full package is sufficient to cause the package to rotate relative to the base plate during stopping and staring. In the new types of winders described above, the edge of the base plate which presses against the yarn exerts a substantial amount of force and is more than sufficient to cut the yarn in two. As a result, the yarn package is no longer first quality and must either be rewound or sold as second quality. The invention described in this application solves this problem easily, efficiently and inexpensively.